Passing QFlags between threads

iw2lsi

Dear all,

using Qt4.8.7, I'm in trouble trying to connect a signal to a slot on a different thread when signal/slot argument contains a QFlags...

first of all... is this possible at all ?

I'm declaring my flags as usual, with

   Q_DECLARE_FLAGS (ACTRLFLAGS, ACTRLFLAG)

and

    Q_DECLARE_OPERATORS_FOR_FLAGS( NMyClass::ACTRLFLAGS )

but this seems not enougth when the connection is (queued) between threads... then I've try registering the type with

   Q_DECLARE_METATYPE(NMyClass::ACTRLFLAGS)

and

  qRegisterMetaType<NMyClass::ACTRLFLAGS>();

but even if I don't see anymore an error regarding the connection at run-time, it simply doesn't work... my slot is not called at all...

any ideas ?

thanks in advance

Giampaolo

[Added code tags ~kshegunov]

SGaist

Hi,

IIRC, you need to also provide the QDataStream operators for your flags and register them with qRegisterMetaTypeStreamOperators so they can be serialised in QVariant.

iw2lsi

Hello SGaist...

just for a test, I've replaced my QFlags with a plain int... and it doesn't work.... so the problem must be elsewhere...

I'll try again tomorrow :D :D :D

Best Regards

           Giampaolo

jsulm

@iw2lsi Does it work in the same thread?

ambershark

@iw2lsi Show us the code for the signal, slot, and where you connect one to the other.

And if possible the code for the thread start and creation.

kshegunov

@iw2lsi said in Passing QFlags between threads:

qRegisterMetaType<NMyClass::ACTRLFLAGS>();
but even if I don't see anymore an error regarding the connection at run-time, it simply doesn't work... my slot is not called at all...

Depending on how you do the signal-slot connection and/or slot call you may need to adjust this line. Please show us the code for that as @ambershark mentioned.

iw2lsi

Hi all,

first of all, thanks for the support and sorry for the delay...

The problem was in my receiver thread... basically my consumer process was blocking the event loop in a waitcondition, and that's why I was not receiving the signals... Nothing was wrong in the way my QFlags was registered on the meta-object system...

 thanks again,

          Giampaolo